Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds real value beyond them: the active-scene/on-air semantics and the response caps ('20 scenes at a time and at most 50 layer summaries per scene'). It's slightly redundant with the limit/offset schema docs on the 20-scene cap.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Four short sentences, front-loaded with what the tool does, then the domain concept, then the read/list rule, then downstream routing. No filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description carries the return-value burden and does so reasonably: it says scenes come back with layer summaries, states the pagination caps, and warns that layer summaries are truncated at 50. It stops short of describing the fields in a scene or layer summary, a minor gap.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% — limit, offset, sceneId and projectId are all documented, including the nextOffset pagination hint and the 24-hex pattern. The description restates the sceneId presence/absence behavior but adds no format or syntax detail beyond the schema, so the baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Read the scenes of a project') and adds domain definition: 'A scene is one arrangement of content; exactly one scene is active at a time.' This distinguishes it from siblings like livereacting_get_layer and livereacting_activate_scene that operate on adjacent concepts.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicit branching rule: 'Give a sceneId to read a single scene, or leave it out to list them all.' It also names the precise downstream workflows — find a layer id before livereacting_get_layer / livereacting_set_playlist, and a scene id before livereacting_activate_scene.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.